1. Field of the Invention
The present invention relates to a mirror driving method and device for a photographic printer, in which a mirror is moved into and out of a printing light path for light measurement, before printing.
2. Related Art
A photographic printer is known from Japanese Laid-open Patent Application No. 2-278248 (corresponding U.S. Pat. No. 5,006,886), wherein a zoom lens is used as a printing lens for making prints of a predetermined size from photographic films having relatively small sizes, such as 110 film and 135 film, by changing the focal length of the zoom lens according to the film size. When making prints from a film having large frames, such as 120 film, a corresponding fixed focus lens is set in the printing light path in place of the zoom lens. Since such a printing of large frames is not required as frequently, the necessity of changing lenses is reduced, and the efficiency of printing is improved.
In the above-mentioned known photographic printer, the zoom lens is attached at one end thereof with a prism. The prism reflects part of the printing light passing through a photographic film, and directs the reflected light perpendicularly with respect to the printing light path toward a light measuring system. The light measuring system includes a photometric zoom lens and a beam splitter. The focal length of the photometric zoom lens is changed according to the frame size to be printed. The beam splitter divides the light traveling through the photometric zoom lens in half by partially reflecting and transmitting the light. The transmitted light is received on an image sensor for exposure calculation, and the reflected light is received on an image sensor for monitoring.
On the other hand, when a fixed focus lens is set in the printing light path, for example, for printing 120 film, a mirror is placed between the photographic film and the fixed focus lens during light measurement. The mirror reflects the printing light passing through the photographic film and directs the light toward the light measuring system. The mirror is movable diagonally with respect to the printing light path, and is removed from the printing light path during printing.
The above-described photographic printer is of the inverted type wherein photographic paper is disposed above the photographic film. Because the space between the mirror positioned in the printing light path and a film carrier for holding the photographic film is very narrow in this inverted type photographic printer, it is possible that the mirror might cause injury to the operator if the mirror suddenly moves down into the printing light path while the operator handles the photographic film. Even if the operator may not be injured at that time, the operator would be surprised by the sudden downward movement of the mirror.